To put "shit on toast" is an expression used to describe nothing or nothing desirable. Similar to jack shit or if there was indeed a culinary dish with shit or faeces on warm breed it would be considered undesirable by most.

To put "shit on toast" is an expression of how awesome something is. When you really like something - a song, for example - it is your "jam." And what do we do with jam? We put it on toast. As a result, anything awesome is shit put on toast.

Extremely hung over, often with alcohol seeping from pores and a general feeling of repulse.

When somebody will not leave you alone. Refering to the gravy in Shit on a Shingle ( Creamed Beef on Toast )

an over clocked cpu cooled by liquid nitrogen